@Simon_Robinson Thanks Simon. My initial problem was a need for way more than 100,000 rows, and that was suggested as a possibility. But the fatal problem that has now emerged is the non-support of databases under new pricing for publisher pro.

@Robert_Lerner Simon, it turns out that the problem is a hard 100,000 row limit with AppSheet - Google Sheet has no problem. Unfortunately, this otherwise really nice platform appears to no longer be usable for public-facing apps having fairly large files. A lot of wasted time on my part. Thanks again for trying to help.